The present invention relates generally to a portable apparatus that is designed as a miniaturized handheld device for cardiovascular function monitoring that can be used in either hospital or household. More specifically, the cardiovascular function monitor presented here is capable of detecting movements of skin surface due to the contraction(s) of the heart or blood vessels; or to turbulent blood flow through the heart or the blood vessels. The implementation of such portable equipment is based on a non-invasive method using optical interferometric laser scanning beam as the probing signal published in U.S. patent application Ser. No. 15/146,354, filed May 4, 2016, entitled “Interferometric focusing beam optical cardiovascular sensor”.
Detection and monitoring of the activities of the heart or the blood vessels provide important physiological and pathological information on the cardiovascular system function of human body. Pumping action of the heart produces beats and closing of heart valves produces sounds, movement of the arteries contributes to the propagating pulses and turbulent blood flow through narrowed arteries produces arterial bruit [e.g., the blowing/swishing sound in a stenosed (narrowed) carotid artery] and so on. These cardiovascular signals which reflect functions of the Circulatory (Cardiovascular) System can be assessed by modern techniques, such as ultrasound-visualization, electro-cardiography (ECG), or auscultation with a stethoscope etc. However, none of these methods provides complete information on both the heart and the blood vessels. Also, there are numerous situations under which ordinary techniques are hampered, e.g., the heart sound(s) collected using an ordinary stethoscope is (are) faint or not even audible as the result of ambient noises. Furthermore, as cardiovascular diseases need early detection of the risks, none of these methods provides early enough diagnosis unless severe events bring the patients to the hospital. Therefore, it is the broad object of the present invention to provide a novel portable optical scanning detection system, wherein and whereby, cardiovascular signals as a result of the contractions of the heart or blood vessels, or turbulent blood flow through the heart chambers, valves, or blood vessels, could be detected and quantified, such that abnormalities, if any, of the cardiovascular function could be identified, quantitatively, at early-stage.
The following U.S. patents describe various prior art systems related to the above discussed problems but do not satisfy the long felt but unsolved need for portable, miniaturized multi-functional device that can perform multiple detection schemes at a minimum cost level:
U.S. Pat. No. 7,024,001, issued Apr. 4, 2006, to Tsutomu Nakada, Tokyo, discloses a laser based stethoscope that a radiation/light-receiving fiber, serving as a probe part for noninvasively irradiating with near-infrared light, is applied to the diseased part so as to measure, e.g., a change of the cerebral circulation blood flow. In this design, three semiconductor laser light sources with wavelengths λ=760, 800, 830 nm are used and applied to the diseased part, the reflection data from the diseased part is processed by a control device. The doctor can then “make a diagnosis with the doctor's ears by hearing with a receiver the change as the change of the frequency of the sound the pitch and volume of which are constant.” This invention helps the detection on blood flow turbulence, but lacks solution on detecting other vital cardiovascular events, such as heart beat, heart sound, pulse wave, etc.
U.S. Pat. No. 7,128,714, issued Oct. 31, 2006, which proposes a non-contact method and an apparatus for continuously monitoring a physiological event in human or animals, namely blood pressure, involves utilizing a laser-based interferometer system to produce a waveform that is representative of continuous blood pressure in a subject. The invention utilizes a laser Doppler vibrometer which is substantially perpendicular to a skin surface of the subject wherein the skin surface is moveable in response to blood pressure. The principle and implementation of the invention is novel though its size, cost and applications are limited due to the traditional laser Doppler vibrometers.